Tropica CO2 Diffuser 3-in-1

The Tropica CO2 Diffuser 3-in-1 combines a bubble counter, a reflux valve and a ceramic diffuser in one unit. It is made as part of the CO2 system of a planted aquarium: one unit replaces three separate parts on the CO2 hose.

The ceramic disc creates fine micro-bubbles, so according to the manufacturer more of the CO2 is used than with a regular air stone. The bubbles in the counter chamber are large and easy to count. The reflux valve stops aquarium water from flowing back into the hose, which can happen when the CO2 cylinder runs empty or a solenoid valve shuts off the CO2 at night.

The diffuser attaches to the aquarium glass with suction cups. Clean the glass and remove any grease before fitting so the suction cups hold well; the manufacturer recommends an ultra-thin layer of Vaseline on the suction cups. To set the CO2 dose, count the bubbles in the counter while turning the regulator.